The present invention can provide a resin composition comprising epoxy-modified polyphenylene ethers which show good solubility in MEK or acetone which has been conventionally used in a manufacturing process for printed boards of epoxy resins, and has high heat resistance originating from polyphenylene ethers. Specifically, the resin composition of the present invention contains (C) an epoxy-modified polyphenylene ether obtained by reacting (A) a polyphenylene ether having a content of volatile components of 0.1-5.0% by weight and a number of average molecular weight of 500 or more and less than 1.0.times.10.sup.4 and (B) a cresol-novolac type epoxy resin at a modification ratio of component (A) of 5-95%, wherein (B') a cresol-novolac type epoxy resin is contained in an amount of 10-900 parts by weight based on 100 parts by weight of the total of the reaction products (C), and (A') a polyphenylene ether.